I have the Windsor 3800 X2 and it's stable OC'd at 2.7Ghz on air. .
I'm using a ASUS M2N32-Sli Deluxe. The HSF is a Zalman 9500. Also if you go with a good case, it really helps temps. I'm currnetly at 32C idle and 48C load.
My bad. In my heart of hearts, I thought I was looking at S939 CPUs. It is the Manchester I want, unless I change platforms completely.
The processor is a 3800 X2 Windsor (It was in my first post). I'm using Corsair Xtreme PC6400 Cas4 at the 4-4-4-12 2T timings. 2x1 GB. Great memory actually. I really wanted some Mushkin or OCZ but my motherboard has some problems supporting these. I think it's been worked out now. The memory manufactures had to makes some changes on their DIMMS. But I'm very impressed with the Corsair! I actually had the memory stable at like 1078 Mhz. But I really had to put the voltage to it. Didn't want to get them too hot. Corsair rates them at 1.9V but I have been running at 2.75V for a while now. No problems. Clears Memtest98 multiple times with no errors. My case has some really good ventilation which helps keep the sticks cool.
The highest I can hit stable is 2730 Mhz. But it takes a lot of voltage increase. Anything after that doesn't matter what the voltage is. That's the ceiling for me. It will run on stock volts until about 2.4Ghz. Then you have to start bumping it up. I found a happy medium with temps & performance at about 2.65-2.68 Ghz with memory @ 888Mhz on air.
I can actually boot to Windows @ 2.85Ghz and run programs, But it won't run Prime95 or SuperPI with out immediate errors.